Wow, I have this exact same problem! And it only happens with the Avisio theme. As soon as I activate the theme, my text throughout the site goes from left aligned to center aligned.

This even happens when SEOpressor is the only plugin I have activated. As soon as I deactivate the plugin, the text goes back to left alignment. But I can have the plugin activated with the default WordPress theme, and my text is not effected.

I would love to hear the solution for this because I would like to use the theme and plugin together!